<!DOCTYPE html>
<html lang="en" xmlns:v-model="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="UTF-8">
    <title>01vue</title>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="app" >
    birthday<input type="text" v-model:birthday="birthday"><br>
    user.name<input type="text" v-model:user.name="user.name"><br>
    user.age<input type="text" v-model:user.gae="user.age"><br>
</div>


</body>
<script type="text/javascript">
    var app =new Vue({
        el:"#app",
        data:{
            birthday:1616566607104,
            user:{"name":"Hallo","ags":1}
        },
        watch:{
            birthday(newValue,oldValue){
                console.log(newValue);
                console.log(oldValue);
            },
            user:{
                deep:this,
                handler(obj){
                    console.log(obj)
                }

            }

        }
    })

</script>
</html>